In GB-1,071,116 a plate heat exchanger of this kind is shown, at which special elevations are designed for keeping the plates at a distance from each other in every other plate interspace meant for flowing through of a gaseous fluid, which distance is larger than the distance between the plates in the rest of the plate interspaces aimed for the flowing through of a fluid in a liquid state. The special elevations are created on the tops of those ridges that are crossing each other in the plate interspaces for the gaseous fluid.